Signal processing device and image display apparatus including the same

ABSTRACT

Disclosed is a signal processing device and an image display apparatus including the same. The signal processing device and the image display apparatus comprise: a first reduction unit to receive a image signal and reduce noise of the received image signal, and a second reduction unit to perform grayscale amplification based on the image signal from the first reduction unit, wherein the second reduction unit is configured to perform the grayscale amplification so that upper-limit level of grayscale of the image signal from the first reduction unit is greater than upper-limit level of grayscale of an OSD signal. Accordingly, OSD area may be uniformly displayed regardless of ambient luminance.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/517,486, filed on Jul. 19, 2019, which claims the benefit of earlierfiling date and right of priority to Korean Patent Application No.10-2018-0103070, filed on Aug. 30, 2018, the contents of which are allhereby incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION 1. Field of the invention

The present disclosure relates to a signal processing device and animage display apparatus including the same and, more particularly, to asignal processing device capable of uniformly displaying OSD arearegardless of ambient luminance and an image display apparatus includingthe same.

2. Description of the Related Art

A signal processing device is a device that performs signal processingbased on a signal of a received image so as to display the image.

For example, the signal processing device may receive a broadcast signalor an HDMI signal, perform signal processing based on the broadcastsignal or the HDMI signal, and output a signal-processed image signal.

Meanwhile, with the development of camera and broadcasting technologies,resolution and a vertical synchronization frequency of a received imagehave improved. Specifically, there is a need of performing image qualityprocessing based on an image having resolution of 4K and a verticalsynchronization of 120 Hz.

Such image quality processing may be performed by a signal processingdevice. For this reason, efforts have been made regarding image qualityprocessing based on a high definition image by the signal processingdevice.

SUMMARY OF THE INVENTION

Therefore, the present disclosure has been made in view of the aboveproblems, and an aspect of the present disclosure is to provide a signalprocessing device capable of uniformly displaying OSD area regardless ofambient luminance, and an image display apparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing device capable of enhancing expression of high grayscale andan image display apparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing device capable of gradually enhancing image quality byperforming multi-stage image quality processing, and an image displayapparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing apparatus capable of enhancing image quality by performingmulti-stage noise reduction based on a received image, and a displayapparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing device capable of enhancing image quality by performingmulti-stage grayscale extension on a received image, and an imagedisplay apparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing device capable of enhancing image quality by performingmulti-stage resolution enhancement based on a received image, and animage display apparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing device capable of outputting image quality of a certain levelor higher in response to input images having various qualities, and animage display apparatus including the same.

Another aspect of the present disclosure is to provide a signalprocessing device capable of uniformly displaying OSD area regardless ofambient luminance in a received image by artificial-intelligentlyanalyzing the object, and an image display apparatus including the same.

In an aspect of the present disclosure, the above and other objects canbe accomplished by the provision of a signal processing device and animage display apparatus comprising: a first reduction unit to receive aimage signal and reduce noise of the received image signal, and a secondreduction unit to perform grayscale amplification based on the imagesignal from the first reduction unit, wherein the second reduction unitis configured to perform the grayscale amplification so that upper-limitlevel of grayscale of the image signal from the first reduction unit isgreater than upper-limit level of grayscale of an OSD signal.

The second reduction unit may not perform grayscale amplification withrespect to the OSD signal.

The OSD signal may be input to the second reduction unit, and the secondreduction unit may perform grayscale amplification on an area except foran OSD area corresponding to the OSD signal.

The signal processing device and the image display apparatus furthercomprises an HDR processor to receive the image signal and performgrayscale conversion on the received image signal, the first reductionunit may reduce noise of grayscale-converted image signal received fromthe HDR processor, and the upper-limit level of the grayscale amplifiedby the second reduction unit may be varied according to the grayscaleconversion mode performed by the HDR processor.

When the second grayscale conversion mode in which the low grayscale isnot emphasized compared to the second gradation mode is performed in theHDR processor, the second reduction unit may perform not a thirdgrayscale conversion mode corresponding to the first grayscaleconversion mode but a forth grayscale conversion mode corresponding tothe second grayscale conversion mode, and upper-limit level of thegrayscale of the forth grayscale conversion mode may be greater thanupper-limit level of the grayscale of third grayscale conversion mode.

The HDR processor may perform grayscale conversion based on the firstgrayscale conversion mode in which low grayscale is highlighted comparedto high grayscale and the high grayscale is saturated, or the secondgrayscale conversion mode in which the low grayscale and the highgrayscale are converted uniformly.

When the second grayscale conversion mode may be performed in the HDRprocessor, the second reduction unit is configured to perform not athird grayscale conversion mode corresponding to the first grayscaleconversion mode but a forth grayscale conversion mode corresponding tothe second grayscale conversion mode, upper-limit level of the grayscaleof the forth grayscale conversion mode may be greater than upper-limitlevel of the grayscale of third grayscale conversion mode.

An output vale of low grayscale in the second grayscale conversion modemay be smaller than an output value of low grayscale in the firstgrayscale conversion mode.

The first reduction unit may perform multi-stage noise reduction basedon grayscale-converted image signal received from the HDR processor.

The first reduction unit may perform increase of grayscale resolution ina first-stage, and the second reduction unit may perform increase ofgrayscale resolution in a second-stage.

The signal processing device and the image display apparatus furthercomprises an enhancement unit positioned between the first reductionunit and the second reduction unit and configured to perform multi-stageresolution enhancement based on a noise-reduced image signal receivedfrom the first reduction unit.

The first reduction unit may comprise a plurality of noise reductionunits configured to reduce noise of the received image signal inmultiple stages.

Each of the plurality of noise reduction units may comprise a temporalnoise reduction unit configured to perform temporal noise reductionusing previous frame data, and a spatial noise reduction unit configuredto perform spatial noise reduction using data around current frame data.

When the received image signal is an interlaced video, a first noisereduction unit of the plurality of noise reduction units may performinterlaced progressive conversion.

The second reduction unit may perform grayscale extension on an areawith a first luminance or higher first luminance the within the imagesignal.

The first reduction unit may comprise a first noise reduction unit forperforming first-stage noise reduction based on the received imagesignal, a second noise reduction unit for performing second-stage noisereduction based on the image signal from the first noise reduction unit,and the second reduction unit may perform grayscale amplification basedon the image signal from the second noise reduction unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 is a diagram illustrating an image display apparatus according toan embodiment of the present disclosure;

FIG. 2 is a block diagram of the image display apparatus shown in FIG.1;

FIG. 3 is a block diagram of a signal processor illustrated in FIG. 2;

FIG. 4A is a diagram illustrating a method for controlling a remotecontroller illustrated in FIG. 2;

FIG. 4B is a block diagram of a remote controller illustrated in FIG. 2;

FIG. 5 is a block diagram of a display shown in FIG. 2;

FIGS. 6A and 6B are diagrams referred to for describing an organic lightemitting display panel shown in FIG. 5;

FIG. 7 is an example of a block diagram of a signal processing deviceaccording to an embodiment of the present disclosure; and

FIGS. 8A to 17 are diagrams referred to for describing operation of thesignal processing device shown in FIG. 7.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the present disclosure will be described in more detailwith reference to the accompanying drawings.

In the following description, with respect to constituent elements usedin the following description, the suffixes “module” and “unit” are usedor combined with each other only in consideration of ease in thepreparation of the specification, and do not have or serve as differentmeanings. Accordingly, the suffixes “module” and “unit” may beinterchanged with each other.

FIG. 1 is a diagram illustrating an image display apparatus according toan embodiment of the present disclosure. Referring to the drawing, animage display apparatus 100 may include a display 180.

Meanwhile, the display 180 may be implemented as any one of variouspanels. For example, the display 180 may be any one of a Liquid CrystalDisplay (LCD) panel, an organic light emitting panel (OLED panel), aninorganic light emitting panel (an LED panel), etc.

The present disclosure will be described mainly about the case where thedisplay 180 includes an organic light emitting panel (OLED).

Meanwhile, compared to an LCD panel, the organic light emitting panel(OLED panel) has a fast response speed and is excellent at expressingcolor.

Accordingly, when the display 180 includes an organic light emittingpanel, it is desirable that a signal processor 170 (see FIG. 2) in theimage display apparatus 100 performs image quality processing tocorrespond to characteristics of the organic light emitting panel.

Meanwhile, the image display apparatus 100 shown in FIG. 1 may be a TV,a monitor, a tablet Pc, a mobile device, etc.

FIG. 2 is a block diagram of the image display apparatus shown inFIG. 1. Referring to FIG. 2, the image display apparatus 100 accordingto an embodiment of the present disclosure may include an image receiver105 a memory 140, a user input interface 150, a sensor unit (not shown),a signal processor 170, the display 180, and an audio output unit 185.

The image receiving unit 105 may include a tuner unit 110, a demodulator120, a network interface 135, and an external device interface 130.

Unlike FIG. 2, the image receiver 105 may include only the tuner unit110, the demodulator 120, and the external device interface 130. Thatis, the image receiver 105 may not include the network interface 135.

The tuner unit 110 selects a Radio Frequency (RF) broadcast signalcorresponding to a channel selected by a user or an RF broadcast signalcorresponding to each of pre-stored channels from among a plurality ofRF broadcast signals received through an antenna (not shown). Inaddition, the tuner unit 110 downconverts the selected RF broadcastsignal into an Intermediate Frequency (IF) signal or a basebandAudio/Video (A/V) signal.

For example, if the selected RF broadcast signal is a digital broadcastsignal, the tuner unit 110 downconverts the selected RF broadcast signalinto a digital IF signal. On the other hand, if the selected RFbroadcast signal is an analog broadcast signal, the tuner unit 110downconverts the selected RF broadcast signal into an analog basebandA/V signal (CVBS/SIF). That is, the tuner unit 110 may process a digitalbroadcast signal or an analog broadcast signal. The analog baseband A/Vsignal, CVBS/SIF from the tuner unit 110 may be provided directly to thesignal processor 170.

Meanwhile, the tuner unit 110 may include a plurality of tuners forreceiving broadcast signals of a plurality of channels, or a singletuner for simultaneously receiving broadcast signals of a plurality ofchannels.

The demodulating unit 120 receives the digital IF signal from the tunerunit 110 and demodulates the digital IF signal.

The demodulating unit 120 may perform demodulation and channel decodingon the digital IF signal, thereby obtaining a stream signal TS. Thestream signal TS may be a signal in which an image signal, an audiosignal and/or a data signal are multiplexed.

The stream signal output from the demodulating unit 120 may be input tothe signal processor 170 and then subjected to demultiplexing and A/Vsignal processing. The signal processor 170 outputs the processed videoand audio signals to the display 180 and the audio output unit 185,respectively.

The external device interface unit 130 may transmit and receive data toand from a connected external device (not shown) such as a set-top box.For this purpose, the external device interface 130 may include an A/VInput/Output (I/O) unit (not shown).

The external device interface unit 130 may be connected to an externaldevice, wirelessly or wiredly, such as a Digital Versatile Disk (DVD)player, a Blu-ray Disk (BD) player, a game console, a camera, acamcorder, a computer (e.g. a laptop computer), or a set-top box. Then,the external device interface 130 may transmit and receive signals toand from the external device.

The A/V input and output unit may receive audio and image signals froman external device, and a wireless communication unit (not shown) mayconduct short-range wireless communication with another electronicdevice.

The external device interface unit 130 may exchange data with a nearbymobile terminal 600 through the wireless communication unit (not shown).Particularly, the external device interface 130 may receive deviceinformation, executed application information, an application image, andso on from the mobile terminal 600 in a mirroring mode.

The network interface unit 135 serves as an interface between the imagedisplay apparatus 100 and a wired/wireless network such as the Internet.For example, the network interface 135 may receive content or data fromthe Internet or from a Content Provider (CP) or a Network Provider (NP)over a network.

Meanwhile, the network interface unit 135 may include a wirelesscommunication unit (not shown).

The memory 140 may store programs necessary for the signal processor 170to process signals and control, and may also store a signal-processedimage, audio, or data signal.

In addition, the memory 140 may also temporarily store an audio, videoor data signal received from the external device interface 130. Thememory 140 may store information about broadcast channels by thechannel-add function.

While the memory 140 is shown in FIG. 2 as configured separately fromthe signal processor 170, to which the present disclosure is notlimited, the memory 140 may be incorporated into the signal processor170.

The user input interface unit 150 transmits a signal received from theuser to the signal processor 170 or transmits a signal received from thesignal processor 170 to the user.

For example, the user input interface 150 may receive user input signalssuch as a power-on/off signal, a channel selection signal, and a screensetting signal from a remote controller 200, provide the signalprocessor 170 with user input signals received from local keys (notshown), such as inputs of a power key, a channel key, a volume key, anda setting value, transmit a user input signal received from the sensorunit (not shown) that senses a user gesture to the signal processor 170,or transmit a signal received from the signal processor 170 to thesensor unit (not shown).

The signal processor 170 may demultiplex a stream signal received fromthe tuner unit 110, the demodulator 120, the network interface 135, orthe external device interface 130 into a number of signals, and processthe demultiplexed signals into audio and image signals.

For example, the signal processor 170 may receive a broadcast signal oran HDMI signal received by the image receiving unit 105, and output aprocessed image signal by processing the received broadcast signal orthe received HDMI signal.

The image signal processed by the signal processor 170 may be displayedas an image corresponding to the image signal on the display 180. Theimage signal processed by the signal processor 170 may also betransmitted to an external output device through the external deviceinterface 130.

The audio signal processed by the signal processor 170 may be output tothe audio output unit 185. Also, the audio signal processed by thesignal processor 170 may be transmitted to an external output devicethrough the external device interface 130.

While not shown in FIG. 2, the signal processor 170 may include aDemultiplexer (DEMUX) and a video processor, which will be describedlater with reference to FIG. 3. That is, the signal processor 170 mayprocess various types of signals and accordingly may be implemented inthe form of a system On Chip (SOC). It will be described in more detailwith reference to FIG. 3.

In addition, the signal processor 170 may provide overall control to theimage display apparatus 100. For example, the signal processor 170 maycontrol the tuner unit 110 to select an RF broadcast signalcorresponding to a user-selected channel or a pre-stored channel.

The signal processor 170 may control the image display apparatus 100according to a user command received through the user input interface150 or according to an internal program.

The signal processor 170 may control the display 180 to display animage. The image displayed on the display 180 may be a Two-Dimensional(2D) or Three-Dimensional (3D) still image or video.

The signal processor 170 may control a particular 2D object in the imagedisplayed on the display 180. For example, the particular 2D object maybe at least one of a linked Web page (e.g. from a newspaper or amagazine), an Electronic Program Guide (EPG), a menu, a widget, an icon,a still image, a video, or text.

The signal processor 170 may locate the user based on an image capturedby a camera unit (not shown). For example, the signal processor 170 maydetermine the distance (a z-axis coordinate) between the user and theimage display apparatus 100. In addition, the signal processor 170 maydetermine x-axis and y-axis coordinates corresponding to the position ofthe user on the display 180.

The display 180 generates drive signals by converting a processed imagesignal, a processed data signal, an On Screen Display (OSD) signal, anda control signal received from the signal processor 170 or an imagesignal, a data signal, and a control signal received from the externaldevice interface 130.

Meanwhile, the display 180 may also be a touch screen that can be usednot only as an output device but also as an input device.

The audio output unit 185 may receive a processed audio signal from thesignal processor 170 and output the received audio signal as voice.

The camera unit (not shown) captures a user. The camera unit mayinclude, but not limited to, a single camera. When needed, the cameraunit may include a plurality of cameras. Image information captured bythe camera unit may be provided to the signal processor 170.

The signal processor 170 may sense a user's gesture from a capturedimage received from the camera unit or from signals received from thesensor unit (not shown) alone or in combination.

A power supply 190 supplies power across the whole image displayapparatus 100. Particularly, the power supply 190 may supply power tothe signal processor 170 which may be implemented as a System On Chip(SOC), the display 180 for displaying an image, the audio output unit185 for outputting an audio signal, and so on.

Specifically, the power supply 190 may include a converter forconverting Alternating Current (AC) power to Direct Current (DC) power,and a DC/DC converter for converting the level of DC power.

The remote controller 200 transmits a user input to the user inputinterface 150. For the transmission of a user input, the remotecontroller 200 may operate based on various communication standards suchas Bluetooth, RF communication, IR communication, Ultra WideBand (UWB),and ZigBee. In addition, the remote controller 200 may receive an imagesignal, an audio signal and/or a data signal from the user inputinterface 150 and may output the received signal as an image or sound.

The above-described image display apparatus 100 may be a fixed or mobiledigital broadcast receiver.

The block diagram of the image display apparatus 100 illustrated in FIG.2 is an exemplary embodiment of the present disclosure. The imagedisplay apparatus 100 is shown in FIG. 15 as having a number ofcomponents in a given configuration. However, the image displayapparatus 100 may include fewer components or more components than thoseshown in FIG. 15. Also, two or more components of the image displayapparatus 100 may be combined into a single component or a singlecomponent thereof may be separated into two more components. Thefunctions of the components of the image display apparatus 100 as setforth herein are illustrative in nature and may be modified, forexample, to meet the requirements of a given application.

FIG. 3 is a block diagram of the signal processor illustrated in FIG. 2.

Referring to FIG. 3, the signal processor 170 may include a DEMUX 310,an image processor 320, a processor 330, and an audio processor 370. Thesignal processor 170 may further include a data processor (not shown).

The DEMUX 310 demultiplexes an input stream. For example, the DEMUX 310may demultiplex an MPEG-2 TS into an image signal, an audio signal, anda data signal. The input stream signal may be received from the tunerunit 110, the demodulator 120, or the external device interface 130.

The image processor 320 may perform signal processing based on areceived image. For example, the image processor 320 may perform imageprocessing based on an image signal demultiplexed by the DEMUX 310.

To this end, the image processor 320 may include a video decoder 325, ascaler 335, an image quality processor 635, a video encoder (not shown),an OSD generator 340, a Fame Rate Converter (FRC) 350, a formatter 360,etc.

The video decoder 325 decodes the demultiplexed image signal, and thescaler 335 scales resolution of the decoded image signal so that theimage signal may be displayed on the display 180.

The video decoder 325 may be provided with decoders that operate inconformance to various standards. For example, the video decoder 325 mayinclude, for example, an MPEG-2 decoder, an H.264 decoder, a 3D videodecoder for a color image a depth image, a decoder for multi-viewimages, and so on.

The scaler 335 may scale a received image signal which is decoded by theimage decoder 325.

For example, when the size or resolution of a received image signal issmall and low, the scaler 335 may upscale the received image signal.When the size or resolution of a received image signal is great andhigh, the scaler 335 may downscale the received image signal.

The image quality processor 635 may perform image quality processingbased on a received image signal which is decoded by the image decoder325.

For example, the image quality processor 635 may reduce noise of areceived image signal, extend grayscale of the received image signal,enhance image resolution, perform High Dynamic Range (HDR)-based signalprocessing, change a frame rate, or perform image quality processing tocorresponding to characteristics of a panel, especially, an organiclight emitting panel.

The OSD generator 340 generates an OSD signal autonomously or accordingto a user input. For example, the OSD generator 340 may generate signalsby which a variety of information is displayed as graphics or text onthe display 180, according to user input signals. The OSD signal mayinclude various data such as a User Interface (UI), a variety of menus,widgets, and icons. The generated OSD signal may include a 2D or 3Dobject.

Further, the OSD generator 340 may generate a pointer to be displayed onthe display 180 based on a pointing signal received from the remotecontroller 200. Especially, the pointer may be generated from a pointingsignal processor (not shown), which may reside in the OSD generator 340.Obviously, the pointing signal processor may be configured separatelyfrom the OSD generator 240.

The FRC 350 may change the frame rate of the received image signal orsimply output the image signal without frame rate conversion.

The formatter 360 may change the format of a received image signal to animage signal to be displayed on the display.

Particularly, the formatter 360 may change the format of a receivedimage signal to correspond to characteristics of a display panel.

Meanwhile, the formatter 360 may change the format of an image signal.For example, the formatter 360 may change the format of a 3D imagesignal to one of various 3D formats such as a side by side format, atop/down format, a frame sequential format, an interlaced format, and achecker format.

The processor 330 may control overall operations in the image displayapparatus 100 or the signal processor 170.

For example, the processor 330 may control the tuner unit 110 to tune toan RF broadcast signal corresponding to a user-selected channel or apre-stored channel.

The processor 330 may control the image display apparatus 100 accordingto a user command received through the user input interface 150 oraccording to an internal program.

In addition, the processor 330 may control data transmission through thenetwork interface 135 or the external device interface 130.

In addition, the processor 330 may control operations of the DEMUX 310and the image processor 320 in the signal processor 170.

The audio processor 370 of the signal processor 170 may process thedemultiplexed audio signal. For the audio signal processing, the audioprocessor 370 may have a plurality of decoders.

The audio processor 370 of the signal processor 170 may also adjust thebass, treble, and volume of the audio signal.

The data processor (not shown) of the signal processor 170 may processthe data signal obtained by demultiplexing the input stream signal. Forexample, if the demultiplexed data signal is a coded data signal, thedata processor may decode the coded data signal. The coded data signalmay be an EPG which includes broadcasting information specifying thestart time, end time, and the like of a scheduled broadcast program ofeach channel.

Meanwhile, the block diagram of the signal processor 170 illustrated inFIG. 3 is purely exemplary. Depending upon the specifications of thesignal processor 170 in actual implementation, the components of thesignal processor 170 may be combined or omitted or new components may beadded.

In particular, the FRC 350 and the formatter 360 may be providedseparately from the image processor 320.

FIG. 4A is a diagram illustrating a method for controlling the remotecontroller illustrated in FIG. 2.

(a) of FIG. 4A illustrates a pointer 205 representing movement of theremote controller 200, displayed on the display 180.

The user may move or rotate the remote controller 200 up and down, sideto side ((b) of FIG. 4A), and back and forth ((c) of FIG. 4A). Thepointer 205 displayed on the display 180 corresponds to movement of theremote controller 200. Since the pointer 205 moves in accordance withthe movement of the remote controller 200 in a 3D space, the remotecontroller 200 may be referred to as a spatial remote controller or a 3Dpointing device.

Referring to (b) of FIG. 4A, if the user moves the remote controller 200to the left, the pointer 205 moves to the left on the display 180.

A sensor of the remote controller 200 detects the movement of the remotecontroller 200 and transmits motion information corresponding to theresult of the detection to the image display apparatus. Then, the imagedisplay apparatus may determine the movement of the remote controller200 based on the motion information received from the remote controller200, and calculate the coordinates of a target point to which thepointer 205 should be shifted in accordance with the movement of theremote controller 200 based on the result of the determination. Theimage display apparatus then displays the pointer 205 at the calculatedcoordinates.

Referring to (c) of FIG. 4A, while pressing a predetermined button ofthe remote controller 200, the user moves the remote controller 200 awayfrom the display 180. Then, a selected area corresponding to the pointer205 may be zoomed in and enlarged on the display 180. On the contrary,if the user moves the remote controller 200 toward the display 180, theselection area corresponding to the pointer 205 is zoomed out and thuscontracted on the display 180. On the other hand, when the remotecontroller 200 moves away from the display 180, the selection area maybe zoomed out and when the remote controller 200 approaches the display180, the selection area may be zoomed in.

With the predetermined button pressed in the remote controller 200, theup, down, left and right movements of the remote controller 200 may beignored. That is, when the remote controller 200 moves away from orapproaches the display 180, only the back and forth movements of theremote controller 200 are sensed, while the up, down, left and rightmovements of the remote controller 200 are ignored. Unless thepredetermined button is pressed in the remote controller 200, thepointer 205 moves in accordance with the up, down, left or rightmovement of the remote controller 200.

The speed and direction of the pointer 205 may correspond to the speedand direction of the remote controller 200.

FIG. 4B is a block diagram of the remote controller illustrated in FIG.2. Referring to FIG. 4B, the remote controller 200 may include awireless communication unit 425, a user input unit 435, a sensor unit440, an output unit 450, a power supply 460, a memory 470, and a signalprocessor 480.

The wireless communication unit 425 transmits signals to and/or receivessignals from one of image display apparatuses according to embodimentsof the present disclosure. One of the image display apparatusesaccording to embodiments of the present disclosure, that is, the imagedisplay apparatus 100 will be taken as an example.

In this embodiment, the remote controller 200 may include an RF module421 for transmitting RF signals to and/or receiving RF signals from theimage display apparatus 100 according to an RF communication standard.Further, the remote controller 200 may include an IR module 423 fortransmitting IR signals to and/or receiving IR signals from the imagedisplay apparatus 100 according to an IR communication standard.

In this embodiment, the remote controller 200 may transmit a signalcarrying information about movement of the remote controller 200 to theimage display apparatus 100 through the RF module 421.

Further, the remote controller 200 may receive signals from the imagedisplay apparatus 100 through the RF module 421. The remote controller200 may transmit commands, such as a power on/off command, a channelswitching command, or a sound volume change command, to the imagedisplay apparatus 100 through the IR module 423, as needed.

The user input unit 435 may include a keypad, a plurality of buttons, atouch pad, or a touch screen. The user may enter commands to the imagedisplay apparatus 100 by manipulating the user input unit 435. If theuser input unit 435 includes a plurality of hard-key buttons, the usermay input various commands to the image display apparatus 100 bypressing the hard-key buttons. If the user input unit 435 includes atouch screen displaying a plurality of soft keys, the user may inputvarious commands to the image display apparatus 100 by touching the softkeys. The user input unit 435 may also include various input tools otherthan those set forth herein, such as a scroll key and/or a jog key,which should not be construed as limiting the present disclosure.

The sensor unit 440 may include a gyro sensor 441 and/or an accelerationsensor 443. The gyro sensor 441 may sense the movement of the remotecontroller 200.

For example, the gyro sensor 441 may sense motion information about theremote controller 200 in X-, Y-, and Z-axis directions. The accelerationsensor 443 may sense the moving speed of the remote controller 200. Thesensor unit 440 may further include a distance sensor for sensing thedistance between the remote controller 200 and the display 180.

The output unit 450 may output a video and/or audio signal correspondingto a manipulation of the user input unit 435 or a signal transmitted bythe image display apparatus 100. The user may easily identify whetherthe user input unit 435 has been manipulated or whether the imagedisplay apparatus 100 has been controlled based on the video and/oraudio signal output from the output unit 450.

For example, the output unit 450 may include an LED module 451 which isturned on or off whenever the user input unit 435 is manipulated orwhenever a signal is received from or transmitted to the image displayapparatus 100 through the wireless communication unit 425, a vibrationmodule 453 which generates vibrations, an audio output module 455 whichoutputs audio data, or a display module 457 which outputs an image.

The power supply 460 supplies power to the remote controller 200. If theremote controller 200 is kept stationary for a predetermined time orlonger, the power supply 460 may, for example, cut off supply of powerto the remote controller 200 in order to save power. The power supply460 may resume supply of power if a specific key on the remotecontroller 200 is manipulated.

The memory 470 may store various programs and application data forcontrolling or operating the remote controller 200. The remotecontroller 200 may wirelessly transmit signals to and/or receive signalsfrom the image display apparatus 100 in a predetermined frequency bandthrough the RF module 421. The signal processor 480 of the remotecontroller 200 may store information regarding the frequency band usedfor the remote controller 200 to wirelessly transmit signals to and/orwirelessly receive signals from the paired image display apparatus 100in the memory 470 and may then refer to this information for use at alater time.

The signal processor 480 provides overall control to the remotecontroller 200. For example, the signal processor 480 may transmit asignal corresponding to a key manipulation detected from the user inputunit 435 or a signal corresponding to motion of the remote controller200, as sensed by the sensor unit 440, to the image display apparatus100 through the wireless communication unit 425.

The user input interface 150 of the image display apparatus 100 mayinclude a wireless communication module 411 which wirelessly transmitssignals to and/or wirelessly receives signals from the remote controller200, and a coordinate calculator 415 which calculates coordinatesrepresenting the position of the remote controller 200 on the displayscreen, which is to be moved in accordance with the movement of theremote controller 200.

The user input interface 150 may wirelessly transmit RF signals toand/or wirelessly receive RF signals from the remote controller 200through an RF module 412. In addition, the user input interface 150 maywirelessly receive IR signals from the remote controller 200 through anIR module 413 according to the IR communication standard.

The coordinate calculator 415 may receive motion information regardingthe movement of the remote controller 200 through the wirelesscommunication module 411 and may calculate coordinates (x, y)representing the position of the pointer 205 on a screen of the display180 by correcting the motion information for possible errors or userhand tremor.

A signal received in the image display apparatus 100 from the remotecontroller 200 through the user input interface 150 may be transmittedto the signal processor 170. Then, the signal processor 170 may acquireinformation regarding the movement of the remote controller 200 andinformation regarding a key manipulation detected from the remotecontroller 200 from the signal received from the remote controller 200,and may control the image display apparatus 100 based on the acquiredinformation.

In another example, the remote controller 200 may calculate thecoordinates of a position to which the pointer is to be shifted incorrespondence with its movement and output the coordinates to the userinput interface 150 of the image display apparatus 100. In this case,the user input interface 150 may transmit information about the pointercoordinates which was not corrected for possible errors or user handtremor to the signal processor 170.

In a further example, unlike the configuration of the remote controller200 illustrated in FIG. 17B, the coordinate calculator 415 may reside inthe signal processor 170, instead of the user input interface 150.

FIG. 5 is a block diagram of the display shown in FIG. 2.

Referring to the drawing, an organic light emitting panel-based display180 may include an organic light emitting display 210, a first interface230, a second interface 231, a timing controller 232, a gate driver 234,a data driver 236, a memory 240, a processor 270, a power supply 290, acurrent detector 510, etc.

The display 180 may receive an image signal Vd, a first DC power V1, anda second DC power V2, and display a specific image based on an imagesignal.

Meanwhile, the first interface 230 of the display 180 may receive theimage signal Vd and the first DC power V1 from the signal processor 170.

The first DC power V1 may be used to operate the power supply 290 andthe timing controller 230 in the display 180.

The second interface 231 may receive the second DC power V2 from anexternal power supply 190.

The timing controller 232 may output a data driving signal Sda and agate driving signal Sga based on the image signal Vd.

For example, when the first interface 230 outputs a converted imagesignal va1 by converting the received image signal Vd, the timingcontroller 232 may output the data driving signal Sda and the gatedriving signal Sga based on the converted image signal va1.

The timing controller 232 may further receive a control signal and avertical synchronization signal in addition to the image signal vd fromthe signal processor 170.

In addition, the timing controller 232 may output a gate driving signalSga for operating the gate driver 234 and a data driving signal Sda foroperating the data driver 236, based on the control signal and thevertical synchronization signal Vsync in addition to the image signalVd.

In the case where the panel 210 includes RGBW subpixels, the datadriving signal Sda may be a data driving signal for operating the RGBWsubpixels.

Meanwhile, the timing controller 232 may further output a control signalCs to the gate driver 234.

In accordance with the gate driving signal Sga and the data drivingsignal Sda from the timing controller 232, the gate driver 234 and thedata driver 236 supply a scan signal and an image signal through gatelines GL and data lines DL, respectively. Accordingly, the organic lightemitting panel 210 displays the specific image.

Meanwhile, the organic light emitting panel 210 may include an organiclight emitting layer, and a plurality of gate lines GL and a pluralityof data lines DL may cross each other in a matrix form at each pixelcorresponding to the organic light emitting layer.

Meanwhile, the data driver 236 may output a data signal to the organiclight emitting panel 210 based on the second DC power V2 from the secondinterface 231.

The power supply 290 may supply various types of power to the gatedriver 234, the data driver 236, the timing controller 232, etc.

The current detector 510 may detect a current flowing in a subpixel ofthe organic light emitting panel 210. The detected current may be inputto the processor 270 or the like to calculate accumulated currents.

The processor 270 may perform various control operations in the display180. For example, the processor 270 may control the gate driver 234, thedata driver 236, the timing controller 232, etc.

Meanwhile, the processor 270 may receive information on a currentflowing in a subpixel of the organic light emitting panel 210 from thecurrent detector 510.

In addition, the processor 270 may calculate accumulates currents in asubpixel of the organic light emitting panel 210 based on theinformation on a current flowing in the subpixel of the organic lightemitting panel 210. The calculated value of the accumulated currents maybe stored in the memory 240.

Meanwhile, when accumulated currents in a subpixel of the organic lightemitting panel 210 is greater than a threshold level, the processor 270may determine that the subpixel burns-in.

For example, when accumulated currents in a subpixel of the organiclight emitting panel 210 is equal to or greater than 300000 A, theprocessor 270 may determine that the subpixel burns-in.

Meanwhile, when accumulated currents in some of subpixels of the organiclight emitting panel 210 is close to a threshold level, the processor270 may determine that the corresponding subpixels are burn-in expectedsubpixels.

Meanwhile, based on a current detected by the current detector 510, theprocessor 270 may determine that a subpixel having the greatestaccumulated currents is a burn-in expected subpixel.

FIGS. 6A and 6B are diagrams referred to for describing the organiclight emitting display panel shown in FIG. 5.

First, FIG. 6A is a diagram illustrating a pixel in the organic lightemitting panel 210.

Referring to the drawings, the organic light emitting panel 210 may havea plurality of scan lines Scan 1 to Scan n, and a plurality of datalines R1,G1,B1,W1˜Rm,Gm,Bm,Wm intersecting therewith.

Meanwhile, a pixel is defined in an area where scan lines and data linesare intersecting with each other in the organic light emitting panel210. In the drawing, a pixel Pixel 1 having RGBW subpixels SR1, SG1,SB1, and SW1 is illustrated.

FIG. 6B illustrates a circuit of any one subpixel in a pixel of theorganic light emitting panel shown in FIG. 6A.

Referring to the drawing, a circuit CRTm of an organic light emittingsubpixel may be an active type and include a scan switching device SW1,a storage capacitor Cst, a drive switching device SW2, and an organiclight emitting layer OLED.

The scan switching device SW1 is connected to a scan line at a gateterminal, so that the scan switching device SW1 is turned on by areceived scan signal Vdscan. When turned on, the scan switching deviceSW1 transfers a received data signal Vdata to a gate terminal of thedrive switching device SW2 or one end of the storage capacitor Cst.

The storage capacitor Cst is formed between a gate terminal and a sourceterminal of the drive switching device SW2, and stores a specificdifference between a level of a data signal transferred to one end ofthe storage capacitor Cst and a level of DC power VDD transferred to theother end of the storage capacitor Cst.

In one example, if data signals have different levels according to aPulse Amplitude Modulation (PAM) method, a different power level isstored in the storage capacitor Cst due to the level difference of thedata signal Vdata.

In another example, if a data signal has a different pulse widthaccording to a Pulse Width Modulation (PWM) method, a different powerlevel is stored in the storage capacitor Cst due to a pulse widthdifference of the data signal Vdata.

The drive switching device SW2 is turned on by a power level stored inthe storage capacitor Cst. When the drive switching device SW2 is turnedon, a driving current (IOLED) proportional to the stored power levelflows in the organic light emitting layer (OLED). Accordingly, theorganic light emitting layer OLED emits light.

The organic light emitting layer (OLED) may include an RGBW lightemitting layer EML corresponding to subpixels, include at least one of ahole injection layer (HIL), a hole transport layer (HTL), an electrontransport layer (ETL), or an electron injection layer (EIL), and mayadditionally include a hole blocking layer (HBL).

Meanwhile, while subpixels emit white light in the organic lightemitting layer OLED, green, red, and blue subpixels have additionalcolor filters to realize colors. That is, the green, red, and bluesubpixels further have green, red, and blue color filters, respectively.Meanwhile, a while subpixel outputs white light and thus does not needan additional color filter.

Meanwhile, the drawing shows the case where the scan switching deviceSW1 and the drive switching device SW2 are p-type MOSFETs, but the scanswitching device SW1 and the drive switching device SW2 may be n-typeMOSFETs or any other switching devices, such as JFET, IGBT, or SIC.

A pixel is a hold-type device which, after a scan signal is applied,keeps emitting light in the organic light emitting layer OLED during aunit display period, specifically, during a unit frame.

Meanwhile, in the case where the image display apparatus 100 has theorganic light emitting panel 210, if an image displayed on the organiclight emitting panel 210 becomes brighter, power consumption increasesbecause the organic light emitting panel 210 is a self-emitting device.

To prevent the power consumption from increasing, a technique forreducing power consumption when displaying a bright image on the organiclight emitting panel 210 has been adopted. Due to use of this technique,the peak luminance of a bright image is reduced and this deterioratesthe 3D effect.

In order to compensate for reduction in a peak luminance and adeteriorated 3D effect of an image on the organic light emitting panel210, the present disclosure proposes a method ofartificial-intelligently analyze an object in a received image signaland enhancing the 3D effect of the object.

With the development of camera and broadcasting technologies, resolutionand a vertical synchronization frequency of a received image signal haveimproved. In particular, there is a need of performing image qualityprocessing based on an image signal having resolution of 4K and avertical synchronization frequency of 120 Hz. Accordingly, a method forenhancing image quality of a received image signal is proposed. Adecryption thereof will be provided after FIG. 7.

FIG. 7 is an example of a block diagram of a signal processing deviceaccording to an embodiment of the present disclosure, and FIGS. 8A to 17are diagrams referred to for describing operation of the signalprocessing device shown in FIG. 7.

Meanwhile, a signal processing device 170 shown in FIG. 7 may correspondto the signal processor 170 shown in FIG. 2.

First, referring to FIG. 7, the signal processing device 170 accordingto an embodiment of the present disclosure may include an image analyzer610 and an image quality processor 635.

The image analyzer 610 may analyze a received image signal and outputinformation regarding the analyzed image signal.

Meanwhile, the image analyzer 610 may separate an object area and abackground area of a first received image signal. Alternatively, theimage analyzer 610 may calculate a probability or a proportion of anobject area and a background area of the first received image signal.

A received image signal may be a received image signal from the imagereceiver 105, or a video decoded by the video decoder 325 shown in FIG.3.

In particular, using artificial intelligence (AI), the image analyzer610 may analyze a received image signal and output information on theanalyzed image signal.

Specifically, the image analyzer 610 may analyze resolution, grayscale,a noise level, and pattern of a received image signal, and outputinformation regarding the analyzed image signal, especially videoquality setting information, to the image quality processor 635.

The image quality processor 635 may include an HDR processor 705, afirst reduction unit 710, an enhancement unit 750, and a secondreduction unit 790.

The HDR processor 705 may receive an image signal and perform HighDynamic Range (RDR) processing based on the received image signal.

For example, the HDR processor 705 may convert a Standard Dynamic Range(SDR) image signal into an HDR image signal.

In another example, the HDR processor 705 may receive an image signaland perform grayscale processing based on the received image signal forHDR.

Meanwhile, when a received image signal is an SDR image signal, the HDRprocessor 705 may bypass grayscale conversion. When a received imagesignal is an HDR image signal, the HDR processor 705 may performgrayscale conversion. Accordingly, expression of high grayscale of areceived image may improve.

Meanwhile, the HDR processor 705 may perform grayscale conversion basedon a first grayscale conversion mode in which low grayscale ishighlighted compared to high grayscale and the high grayscale issaturated, and a second grayscale conversion mode in which the lowgrayscale and the high grayscale are converted somewhat uniformly.

For example, in (a) of FIG. 8F, a first grayscale conversion curve CVacorresponding to the first grayscale conversion mode and a secondgrayscale conversion curve CVb corresponding to the second grayscaleconversion mode are exemplarily illustrated.

The HDR processor 705 may perform grayscale conversion based on thefirst grayscale conversion curve CVa or the second grayscale conversioncurve CVb.

For example, the HDR processor 705 may perform grayscale conversionbased on data in a lookup table corresponding to the first grayscaleconversion curve CVa or data in a lookup table corresponding to thesecond grayscale conversion curve CVb.

Specially, when the first grayscale conversion mode is performed, theHDR processor 705 may perform grayscale conversion based on data in thelookup table corresponding to the first grayscale conversion mode.

More specially, in the case where the first grayscale conversion mode isperformed, the HDR processor 705 may perform grayscale conversion basedon an arithmetic expression related to input data and data in the lookuptable corresponding to the first grayscale conversion mode determinedaccording to the arithmetic expression. Here, the input data may includevideo data and meta data.

Meanwhile, when the second grayscale conversion mode is performed, theHDR processor 705 may perform grayscale conversion based on data in thelookup table corresponding to the second grayscale conversion mode.

More specifically, in the case where the second grayscale conversionmode is performed, the HDR processor 705 may perform grayscaleconversion based on an arithmetic expression related to input data anddata in a lookup table corresponding to a second grayscale conversionmode determined according to the above arithmetic expression. Here, theinput data may include video data and meta data.

Meanwhile, the HDR processor 705 may select the first grayscaleconversion mode or the second grayscale conversion mode according to athird grayscale conversion mode or a fourth grayscale conversion mode ina high-grayscale amplifier 851 of the second reduction unit 790.

In (b) of FIG. 8F, a third grayscale conversion curve CVc correspondingto the third grayscale conversion mode and a fourth grayscale conversioncurve CVd corresponding to the fourth grayscale conversion mode areexemplarily illustrated.

For example, when the third grayscale conversion mode is performed, thehigh-grayscale amplifier 851 in the second reduction unit 790 mayperform gray level conversion based on data in the lookup tablecorresponding to the third grayscale conversion mode.

Specially, when the third grayscale conversion mode is performed, thehigh-grayscale amplifier 851 in the second reduction unit 790 mayperform grayscale conversion based on an arithmetic expression relatedto input data and data in a lookup table corresponding to a thirdgrayscale conversion mode determined according to the above arithmeticexpression. Here, the input data may include video data and meta data.

Meanwhile, in the case where the fourth grayscale conversion mode isperformed, the high gradation level amplifier 851 in the secondreduction unit 790 may perform grayscale conversion based on data in thelookup table corresponding to the fourth grayscale conversion mode.

Specifically, in the case where the fourth grayscale conversion mode isperformed, the high-grayscale amplifier 851 in the second reduction unit790 may perform grayscale conversion based on an arithmetic expressionrelated to input data and data in a lookup table corresponding to aforth grayscale conversion mode determined according to the abovearithmetic expression. Here, the input data may include video data andmeta data.

In one example, when the fourth grayscale conversion mode is implementedin the high grayscale amplifier 851 of the second reduction unit 790,the HDR processor 705 may implement the second grayscale conversionmode.

In another example, when the third grayscale conversion mode isimplemented in the high-grayscale amplifier 851 of the second reductionunit 790, the HDR processor 705 may implement the first grayscaleconversion mode.

Alternatively, the high-grayscale amplifier 851 of the second reductionunit 790 may change a grayscale conversion mode to be implemented,according to a grayscale conversion mode implemented in the HDRprocessor 705.

In one example, when the second grayscale conversion mode is implementedin the HDR processor 705, the high-grayscale amplifier 851 of the secondreduction unit 790 may implement the fourth grayscale conversion mode.

In another example, when the first grayscale conversion mode isimplemented in the HDR processor 705, the high grayscale amplifier 851of the second reduction unit 790 may implement the third grayscaleconversion mode.

Meanwhile, the HDR processor 705 according to an embodiment of thepresent disclosure may implement a grayscale conversion mode so that lowgrayscales and high grayscales are converted uniformly.

That is, the HDR processor 705 may perform grayscale conversion based onthe second grayscale conversion curve CVb rather than the firstgrayscale conversion curve CVa.

Meanwhile, the second reduction unit 790 may implement the fourthgrayscale conversion mode according to the second grayscale conversionmode implemented in the HDR processor 705, and thus amplify theupper-limit level of grayscale of a received image signal. Accordingly,expression of high grayscale of a received image may improve.

Next, the first reduction unit 710 may reduce noise of the receivedimage signal or an image signal processed by the HDR processor 705.

Specifically, the first reduction unit 710 may perform multi-stage noisereduction and first-stage grayscale extension processing based on areceived image signal or an HDR image received from the HDR processor705.

To this end, the first reduction unit 710 may include a plurality ofnoise reduction units 715 and 720 for multi-stage noise reduction, and agrayscale extension unit 725 for grayscale extension.

Next, the enhancement unit 750 may perform multi-stage resolutionenhancement based on an image received from the first reduction unit710.

In addition, the enhancement unit 750 may perform object stereoscopiceffect enhancement. Further, the enhancement unit 750 may perform coloror contrast enhancement.

To this end, the enhancement unit 750 may include a plurality ofresolution enhancement units 735, 738, and 742 for multi-stageresolution enhancement, an object stereoscopic effect enhancement unit745 for enhancement of a stereoscopic effect of an object, and a colorcontrast enhancement unit 749 for color or contrast enhancement.

Next, the second reduction unit 790 may perform second-stage grayscaleextension processing based on a noise-reduced image signal received fromthe first reduction unit 710.

Meanwhile, the second reduction unit 790 may amplify the upper-limitlevel of grayscale of a received signal and extend the grayscale of thereceived signal. Accordingly, expression of high grayscale of a receivedimage may improve.

For example, it is possible to uniformly extend entire grayscale of areceived signal. Accordingly, as uniform grayscale extension isperformed on an area of a received image, expression of high grayscalemay improve.

Meanwhile, the second reduction unit 790 may perform grayscaleamplification and grayscale extension based on a received signal fromthe first grayscale extension unit 725. Accordingly, expression of highgrayscale of a received image may improve.

Meanwhile, when a received image signal is an SDR image signal, thesecond reduction unit 790 may change a degree of amplification based ona user input signal. Accordingly, expression of high grayscale mayimprove in response to a user's setting.

Meanwhile, when a received image signal is an HDR image signal, thesecond reduction unit 790 may perform amplification according to a setvalue. Accordingly, expression of high grayscale of a received image mayimprove.

Meanwhile, when a received image signal is an HDR image signal, thesecond reduction unit 790 may change a degree of amplification based ona user input signal. Accordingly, expression of high grayscale mayimprove in response to a user's setting.

Meanwhile, when extending a grayscale, the second reduction unit 790 maychange a degree of extending the grayscale based on a user input signal.Accordingly, expression of high grayscale may improve in response to auser's setting.

Meanwhile, the second reduction unit 790 may amplify the upper-limitlevel of grayscale according to a grayscale conversion mode implementedin the HDR processor 705. Accordingly, expression of high grayscale of areceived image may improve.

The signal processing device 170 may include an HDR processor 705 whichreceives an image signal and adjusts a luminance of the image signal,and a reduction unit 790 which amplifies the adjusted luminance of theimage signal and increases a resolution of the grayscale of the imagesignal to generate an enhanced image signal. Here, the enhanced imagesignal provides an increased luminance and grayscale resolution of theimage signal while maintaining high dynamic range within the displayedHDR image.

Meanwhile, the luminance range of the image signal is adjusted accordingto a control signal received at the signal processor 170.

The signal processing device 170 may further include an image analyzer.

The image processing apparatus further includes an image analyzer 610for determining whether the received image signal is an HDR signal orstandard dynamic range (SDR) signal, and for generating the controlsignal for providing to the HDR processor 705. Here, the luminance ofthe image signal is adjusted only when the control signal indicates thatthe received image signal is an HDR signal.

Meanwhile, the control signal is received from the controller 170 of theimage display apparatus 100 associated with the signal processing, andcorresponds to the setting of the image display apparatus 100.

Meanwhile, the resolution of the grayscale is increased based on theamplification of the adjusted luminance of the image signal.

Meanwhile, the resolution of the grayscale is increased based on thecontrol signal received at the image display apparatus 100.

Meanwhile, the reduction unit 790 may includes a high-grayscaleamplifier 851 for amplifying the upper-limit level of the grayscale ofthe received signal, and a decontouring unit 842, 844 for expandingincrease the resolution of the grayscale amplified by the high grayscaleamplifier.

The second reduction unit 790 may include a second grayscale extensionunit 729 for second-stage grayscale extension.

Meanwhile, the image quality processor 635 of the signal processingdevice 170 of the present disclosure is characterized by performingfour-stage reduction processing and four-stage image enhancementprocessing, as shown in FIG. 7.

The four-stage reduction processing may include a two-stage noisereduction and a two-stage grayscale extension.

The two-stage noise reduction may be performed by the first and secondnoise reduction units 715 and 720 in the first reduction unit 710. Thetwo-stage grayscale extension may be performed by the first grayscaleextension unit 725 in the first reduction unit 710 and the secondgrayscale extension unit 729 in the second reduction unit 790.

Meanwhile, the four-stage image enhancement processing may includethree-stage resolution enhancement (bit resolution enhancement), andobject stereoscopic effect enhancement.

The three-stage resolution enhancement may be performed by the first tothird resolution enhancement units 735, 738, and 742. The objectstereoscopic effect enhancement may be performed by the objectstereoscopic effect enhancement unit 745.

Meanwhile, a first characteristic of the signal processing device 170 ofthe present disclosure lies in gradually enhancing image quality byapplying an identical or similar algorithm multiple times formulti-stage image quality processing.

To this end, the image quality processor 635 in the signal processingdevice 170 of the present disclosure performs video quality processingby applying an identical or similar algorithm two times or more.

Meanwhile, the identical or similar algorithm employed by the imagequality processor 635 has a different purpose in each stage. Inaddition, compared to performing image quality in a single stage,gradually performing multi-stage image quality processing may cause lessartifacts to occur in an image, and generate a more natural and clearimage processing result.

Meanwhile, by applying the identical or similar algorithm alternativelywith another image quality processing algorithm, it is possible toachieve an effect more than what is expected from simple continuousprocessing.

Meanwhile, another characteristic of the signal processing device 170 ofthe present disclosure lies in performing multi-stage noise reduction.Noise reduction in each stage may include temporal processing andspatial processing. It will be described in more detail with referenceto FIG. 8A.

FIG. 8A is referred to for describing operation of the first and secondnoise reduction units 715 and 720 shown in FIG. 7.

Referring to the drawing, the first and second noise reduction units 715and 720 may perform temporal noise reduction and spatial noisereduction, respectively.

To this end, for first-stage noise reduction, the first noise reductionunit 715 may include a temporal noise reduction unit 810, an IPC unit815, and a spatial noise reduction unit 820.

For second-stage noise reduction, the second noise reduction unit 720may include a temporal noise reduction unit 830 and a spatial noisereduction unit 835.

The temporal noise reduction units 810 and 830 may reduce noise bycomparing previous data and current data. The spatial noise reductionunits 820 and 835 may reduce noise by comparing image data included inthe current data and surrounding image data.

Data used by the temporal noise reduction units 810 and 830 and thespatial noise reduction units 820 and 835 may be frame data or fielddata.

Meanwhile, the first noise reduction unit 715 may reduce noise oforiginal data of a received input image signal.

The second noise reduction unit 720 may remove flicker which occursbetween frames of the received input image signal or which occurs afternoise reduction by the first noise reduction unit 715.

Meanwhile, the IPC unit 815 may be positioned between the temporal noisereduction unit 810 and the spatial noise reduction unit 820, and performinterlaced progressive conversion.

The IPC unit 815 may convert an interlaced image signal into aprogressive image signal especially when a received image signal is aninterlaced video. The IPC unit 815 will be described in more detail withreference to FIG. 8B.

FIG. 8B is a diagram referred to for describing multi-stage noisereduction when an input video is an interlaced video.

Referring to the drawing, a top field of the interlaced image may beprocessed at a first time point and a bottom field of the interlacedvideo may be processed at a second time point.

Specifically, when a received image signal is an interlaced video, atemporal noise reduction unit 810 a may perform, at a first time point,temporal noise reduction using current data To in a top field andprevious data T-2 which is temporal-noise reduced and then stored in amemory 801 a.

In addition, the IPC unit 815 a may perform interlaced progressiveconversion by combining image data in a top field, which istemporal-noise reduced by the temporal noise reduction unit 810 a, andimage data of a previous top field stored in the memory 801 a, which isnoise reduced.

That is, the IPC unit 815 a may output a top field-based frame imagedata on the basis of image data of a top field, which is temporal-noisereduced by the temporal noise reduction unit 810 a.

In addition, the spatial noise reduction unit 820 a may perform spatialnoise reduction based on a top field-based frame image data generated bythe IPC unit 815 a.

Next, when the received image signal represents an interlaced image, atemporal noise reduction unit 810 b may perform temporal noise reductionat a second time point using the current data (T-1) in a bottom fieldand previous data (T-3) which is temporal-noise reduced and stored in amemory 801 b.

In addition, the IPC unit 815 b may perform interlaced progressiveconversion by combining image data in a bottom field, which istemporal-noise reduced by the temporal noise reduction unit 810 b, andimage data in a previous bottom field, which is noise reduced and storedin the memory 801 b.

That is, the IPC unit 815 b may output bottom field-based frame imagedata on the basis of image data in a bottom field, which istemporal-noise reduced by the temporal noise reduction unit 810 b.

In addition, the spatial noise reduction unit 820 b may perform spatialnoise reduction based on bottom field-based frame image data which isgenerated by the IPC unit 815 b.

The second-stage temporal noise reduction unit 830 may perform temporalnoise reduction based on top field-based frame video data processed bythe temporal noise reduction unit 820 a and bottom field-based framevideo data processed by the spatial noise reduction unit 820 b.

The second-stage temporal noise reduction unit 830 may process the topfield-based frame video data and the bottom field-based frame video datatogether, thereby enabled to remove flicker between the top field andthe bottom field, the flicker which has not processed in a previousstage. In conclusion, it is possible to remove artifacts occurring inthe interlaced image.

Meanwhile, another characteristic of the signal processing device 170 ofthe present disclosure lies in performing grayscale reproduction orgrayscale extension in multiple stages.

Grayscale of a received image signal may mean bit resolution, andrepresent respective channels of R, G, B or Y, Cb, Cr.

Meanwhile, the number of bits of image grayscale processed in the signalprocessing device 170 may be 10 bits or more.

Meanwhile, when original data of a received image signal is 10-bit orlower grayscale data, the signal processing device 170 may performgrayscale reproduction processing or grayscale extension processing,thereby enabled to generate or maintain 10-bit or higher grayscale data.

To this end, the image quality processor 635 of the present disclosuremay perform grayscale extension processing in two or more stages. Itwill be described in more detail with reference to FIG. 8C.

FIG. 8C is a diagram referred to for describing grayscale extensionprocessing.

Referring to FIG. 8C, the first grayscale extension unit 725, theenhancement unit 750, and the second grayscale extension unit 729 may beused for grayscale extension processing.

The first grayscale extension unit 725 may perform first-stage grayscaleextension based on an image signal from the HDR processor 705. That is,the first grayscale extension unit 725 may perform first-stage grayscaleextension on a grayscale converted by the HDR processing unit 705.

In particular, for the first-stage grayscale extension, the firstgrayscale extension unit 725 may include decontouring units 842 and 844and a dithering unit 846.

Specifically, the first grayscale extension unit 725 may include a firstdecontouring unit 842 for performing first-stage decontouring, a seconddecoutouring unit 844 for performing second-stage decontouring, and thedithering unit 846 for performing dithering.

The second grayscale extension unit 729 may include a high grayscaleamplifier 851 for high grayscale amplification, a third decontouringunit 852 for performing first-stage decontouring, a fourth decontouringunit 854 for performing second-stage decontouring, and a dithering unit856 for performing dithering.

The first decontouring unit 842 and the third decontouring unit 852reproduces grayscale of a received image signal by performingfirst-stage grayscale extension.

The second decontouring unit 844 may restore a grayscale loss, occurringin an inner process, by performing second-stage grayscale extension.

Meanwhile, the first grayscale extension unit 725 and the secondgrayscale extension unit 729 may let an inner core to pass through eachof the decontouring units 842, 844, 852, and 854 two times or more andgradually increase grayscale at the corresponding core by few bits eachtime. For example, the first grayscale extension unit 725 may reproducegrayscale of each channel up to 14bits

Meanwhile, the grayscale extended by each of the decontouring units 842,844, 852, and 854 may be dithered by the dithering units 846 and 856,and therefore, a loss of information may be minimized.

Meanwhile, the high grayscale amplifier 851 may amplify the upper-limitlevel of grayscale of a received signal. Accordingly, expression of highgrayscale of a received image may improve.

Meanwhile, the third and fourth decontouring units 852 and 854 mayextend the grayscale amplified by the high grayscale amplifier 851.

Meanwhile, the high grayscale amplifier 851 may perform boosting of abright area in an image by amplifying expression of grayscale of thebright area.

For example, the high grayscale amplifier 851 may perform boosting of anarea with a first luminance in an image by amplifying expression ofgrayscale of the corresponding area.

The high grayscale amplifier 851 may discover a light source area or areflected light area of a received image signal and performamplification on the light source area or the reflected light area sothat brightness of the corresponding area exceeds a 10-bit expressionrange (0-1023).

As such, as a light source area or a reflected light area of a receivedimage signal is discovered and the corresponding area is made brighter,it is possible to amplify information of a high grayscale area, therebyproviding an effect similar to an HDR effect.

Meanwhile, the second grayscale extension unit 729 may receive OSDinformation and perform additional image quality processing based on anOSD area.

In this case, the second grayscale extension unit 729 may not performhigh grayscale amplification on the OSD area.

Meanwhile, the high grayscale amplifier 851 may receive an image or OSDinformation from the enhancement unit 750.

For example, when an image is received from the enhancement unit 750,the high grayscale amplifier 851 may perform high grayscaleamplification on the received image. Specifically, the high grayscaleamplifier 851 may amplify the upper-limit level of the maximumgrayscale.

Meanwhile, when OSD information is received, the high grayscaleamplifier 851 may not perform high grayscale amplification on an areacorresponding to the OSD information.

In addition, when other information (e.g., subtitle information or logoinformation) is included in a received image, the high grayscaleamplifier 851 may not perform high grayscale amplification on an areacorresponding to the information (e.g., subtitle information or logoinformation).

Accordingly, an OSD area or other information area may be processed,without high grayscale amplification, by the third decontouring unit 852for performing first-stage decontouring, the fourth decontouring unit854 for performing second-stage decontouring, and the dithering unit 856for performing dithering.

FIG. 8D is a diagram referred to for describing the case where highgrayscale amplification is not performed on an image having an OSD area.

First, (a) of FIG. 9D illustrates an example in which an entire image925 a including a user interface (UI)930 is subject to high grayscaleamplification. In this example, since the UI area 930 is subject tograyscale amplification, the UI area 930 fails to be expressed uniformlydue to ambient luminance.

Next, (b) of FIG. 8D illustrates an example in which a UI area 930 in animage 925 b is not subject to high grayscale amplification but the restof the image 925 b is subject to high grayscale amplification.Accordingly, since the UI area 930 is not subject to high grayscaleamplification, the UI area 930 is able to be expressed uniformly,regardless of ambient luminance.

Specifically, an OSD signal is input to the second reduction unit 790,and the second reduction unit 790 may perform grayscale amplificationand extension on areas, except for an OSD area corresponding to the OSDsignal, based on coordinate information of the OSD signal.

That is, the second reduction unit 790 may not perform grayscaleamplification and extension with respect to the OSD signal.

Accordingly, since the UI area 930 is not subject to high grayscaleamplification and extension, the UI area 930 is able to be expresseduniformly, regardless of ambient luminance.

Meanwhile, due to the high grayscale amplification on an area other thanthe UI area 930, a light source area 940 in the image 925 b is subjectto extension process so as to have brightness exceeding a 10-bitexpression range (0˜1023) and thus is able to be expressed brighter.

Meanwhile, the second reduction unit 790 may perform grayscaleamplification so that the upper-limit level of grayscale of an imagesignal is greater than the upper-limit level of grayscale of an OSDsignal. In this case, it is desirable to perform grayscale conversionsuch that the upper-limit level of the OSD signal is significantlysmaller than the upper-limit level of the image signal despite thegrayscale amplification, or it is desirable that grayscale amplificationis not performed in the first place. Accordingly, the OSD area 930 isable to be expressed uniformly, regardless of ambient luminance.

FIGS. 8E and 8F are diagrams referred to for describing grayscaleconversion by an HDR processor.

First, referring to FIG. 8E, the HDR processor 705 may perform HDRprocessing based on a received image signal.

For example, the HDR processor 705 may convert an SDR video into an HDRvideo or perform grayscale processing for HDR.

For example, as illustrated in (a) of FIG. 8F, the HDR processor 705 mayperform grayscale conversion based on a first grayscale conversion curveCVa which highlights low grayscale compared to high grayscale andsaturates the high grayscale, or a second grayscale conversion curve CVbwhich converts the low grayscale and the high grayscale somewhatuniformly.

According to (a) of FIG. 8F, an output vale of low grayscale Lmd in asecond grayscale conversion mode is smaller than an output value Lva oflow grayscale in a first grayscale conversion mode.

Meanwhile, the HDR processor 705 may perform grayscale conversion basedon the first grayscale conversion curve CVa or the second grayscaleconversion curve CVb in (a) of FIG. 8F.

Meanwhile, the HDR processor 705 according to an embodiment of thepresent disclosure may bypass grayscale conversion when a received imagesignal is an SDR image signal. The HDR processor 705 may performgrayscale conversion when a received image signal is an HDR imagesignal.

For example, when a received image signal is an HDR image signal, theHDR processor 705 according to an embodiment of the present disclosuremay implement a grayscale conversion mode based on the second grayscaleconversion curve CVb so that low grayscale and high grayscale areconverted uniformly.

An HDR image received from the HDR processing unit 705 may be input tothe second grayscale extension unit 729 of the second reduction 790after passing through the first reduction unit 710 and the enhancementunit 750.

Meanwhile, the second grayscale extension unit 729 may receive OSDinformation or other information (e.g., subtitle information or logoinformation) in addition to an image from the enhancement unit 750.

When OSD information or other information (e.g., subtitle information orlogo information) is received, the high grayscale amplifier 851 of thesecond grayscale extension unit 729 may not perform high grayscaleamplification on an area corresponding to the OSD information or otherinformation.

Accordingly, the UI area 930 is not subject to high grayscaleamplification, as shown in (b) of FIG. 8D, and thus, the UI area 930 maybe expressed uniformly, regardless of ambient luminance.

Meanwhile, the high grayscale amplifier 851 may perform high grayscaleamplification on an area other than an area corresponding to OSDinformation or other information in a received HDR image.

Accordingly, amplification and extension processing are performed sothat brightness of the light source area 940 in the image 925 exceeds a10-bit expression range (0˜1023), as shown in (b) of FIG. 8D, and thusis able to be expressed brighter.

Meanwhile, the high grayscale amplifier 851 of the second reduction unit790 may amplify the upper-limit level of grayscale extended by thesecond reduction unit 790, as shown in (b) of FIG. 8B. Accordingly,expression of high grayscale of a received image may improve.

In particular, the high grayscale amplifier 851 of the second reductionunit 790 may amplify the upper-limit level of the maximum grayscale.Accordingly, expression of high grayscale of a received image mayimprove.

In (b) of FIG. 8F, a third grayscale conversion curve CVc correspondingto a third grayscale conversion mode and a fourth grayscale conversioncurve CVd corresponding to a fourth grayscale conversion mode areexemplarily illustrated.

When the third grayscale conversion mode is implemented, the upper-limitlevel of the maximum grayscale Lma is La1. When the third grayscaleconversion mode is implemented, the upper-limit level of the maximumgrayscale Lma is La2 which is much greater than La1.

That is, the high grayscale amplifier 851 of the second reduction unit790 may amplify the upper-limit level of the maximum grayscale Lmaaccording to the fourth grayscale conversion mode. Accordingly,expression of high grayscale of a received image may improve.

Meanwhile, the high grayscale amplifier 851 of the second reduction unit790 may perform grayscale extension on an area with a first luminanceLMu within a received image signal, as shown in (b) of FIG. 8F.

According to the third grayscale conversion curve CVc in (b) of FIG. 8F,the first luminance LMu is converted to a level lower than theupper-limit level La1. However, according to the fourth grayscaleconversion curve CVd, the first luminance LMu is converted to theupper-limit level La1. Thus, according to the fourth grayscaleconversion curve CVd, grayscale of the first luminance LMu or higher maybe converted to a level between La1 and La2. Hence, expression of highgrayscale may improve.

Meanwhile, when grayscale conversion is performed by the HDR processor705 based on the second grayscale conversion curve CVb in (a) of FIG.8F, the high grayscale amplifier 851 may perform high grayscaleamplification and extension based on the fourth grayscale conversioncurve CVd, selected from the third grayscale conversion curve CVc andthe fourth grayscale conversion curve CVd, in order to amplify andextend high grayscale of an HDR image.

According to the fourth grayscale conversion curve CVd, grayscale isamplified to a level above the upper-limit level Lal, and thus, it ispossible to highlight high grayscale and hence highlight an HDR effectmore.

That is, according to HDR processing according to an embodiment of thepresent disclosure, grayscale conversion is performed to highlight bothlow grayscale and high grayscale by the second grayscale conversioncurve CVb, rather than highlighting low grayscale by the first grayscaleconversion curve CVa. In addition, the high grayscale amplifier 851amplifies grayscale to be above the upper-limit level L1 of the fourthgrayscale conversion curve CVd in order to amplify high grayscale.Accordingly, it is possible to highlight the entire grayscale,especially high grayscale, and hence highlight an HDR effect more.

Meanwhile, FIG. 8G is a diagram referred to for describing highgrayscale amplification and extension by the second grayscale extensionunit 729 of the second reduction unit 790.

First, the high grayscale amplifier 851 of the second grayscaleextension unit 729 may amplify an upper-limit level of grayscale of aninput signal, as shown in (a) of FIG. 8G.

Specifically, the high grayscale amplifier 851 of the second grayscaleextension unit 729 may amplify the upper-limit level of grayscale of aninput signal in stages.

In (a) of FIG. 8G, a first amplification mode Sta for amplifying theupper-limit level of grayscale of an input signal to La1, and a secondamplification mode STb for amplifying the upper-limit level of grayscaleof an input signal to La2 are exemplarily illustrated.

In particular, the high grayscale amplifier 851 of the second grayscaleextension unit 729 may amplify the upper-limit level of grayscale of aninput signal according to the second amplification mode STb.Accordingly, expression of high grayscale of a received image mayimprove.

Meanwhile, the third and fourth decontouring units 852 and 854 mayextend grayscale amplified by the high grayscale amplifier 851.

(a) of FIG. 8G, illustrates an example of amplifying the upper-limitlevel of grayscale of an input signal in approximately five stagesaccording to the second amplification mode STb. (b) of FIG. 8Billustrates an example of extending grayscale of an input signal instages, more detailed than five stages, according to an extension modeSTc.

That is, the third and fourth decontouring units 852 and 854 may extendgrayscale of an input signal in more detail, without changing theupper-limit level of the grayscale. Accordingly, expression of highgrayscale may improve.

Specifically, the third and fourth decontouring units 852 and 854 in thesecond reduction unit 790 may uniformly perform grayscale extension onthe entire grayscale areas of an input signal.

Due to the above operation of the second grayscale extension unit 729 inthe second reduction 790, expression of high grayscale of a receivedimage may improve.

FIG. 9A is a diagram referred to for describing multi-stage grayscaleextension.

Referring to the drawing, (a) of FIG. 9A represents a received imagesignal 905 a, and (b) of FIG. 9A represents an image 905 b obtained as aresult of multi-stage decoutouring. It is found that grayscale of abackground area 910 is extended or restored due to the multi-stagedecontouring, compared to (a) of FIG. 9A.

For example, even in the case where original grayscale data is 8 bit,the grayscale may be enhanced or extended to 10-bit or higher throughmulti-stage deconturoing.

FIG. 9B is a diagram referred to for describing high grayscaleamplification.

(a) of FIG. 9B represents a received image signal 915 a, and (b) of FIG.9A represents an image 915 b obtained as a result of high grayscaleamplification processing by the high grayscale amplifier 851. It isfound that a light source area 920 in the image is boosted or amplifieddue to the high grayscale amplification processing.

In particular, due to the high grayscale amplification by the highgrayscale amplifier 851, it is possible to express a brighter area in anoriginal image by amplifying grayscale of the brighter area by 10 bitsor more.

Meanwhile, the fourth characteristic of the signal processing device 170of the present disclosure lies in performing multi-stage resolutionenhancement. In particular, the signal processing device 170 performsresolution enhancement in two or more stages. It will be described inmore detail with reference to FIG. 10.

FIG. 10 is a block diagram of the enhancement unit 750 in FIG. 7.

Referring to the drawing, the enhancement unit 750 may include a firstresolution enhancement unit 735 for first-stage resolution enhancement,a first scaler 737 for scaling, a second resolution enhancement unit 738for second-stage resolution enhancement, a second scaler 739 forscaling, a Frame Rate Converter (FRC) 741 for frame rate conversion, anda third resolution enhancement unit 742 for third-stage resolutionenhancement.

Due to the scalers 737 and 739 respectively interposed between theresolution enhancement units 735, 738, and 742, it is possible toachieve super-resolution effect. By changing resolution in this process,resolution enhancement may be performed.

For example, if the first resolution enhancement unit 735 performsresolution enhancement-related signal processing based on an Full HighDefinition (FHD) image whose grayscale is extended by the firstgrayscale extension unit 725, the first scaler 737 may scale thereceived FHD image to a 4K image.

In addition, if the second resolution enhancement unit 738 performsresolution enhancement-related signal processing based on the 4K imagewhich is scaled by the first scaler 737, the second scaler 739 may scalethe received 4K image to a 4K or higher image. For example, the secondscaler 739 may output an overscanned version of the 4K image.

In addition, the third resolution enhancement unit 742 may performresolution enhancement-related signal processing based on theoverscanned version of the 4K image which is scaled by the second scaler739.

That is, the enhancement unit 750 may perform resolution enhancement inthe total three stages through the first resolution enhancement unit735, the second resolution enhancement unit 738, and the thirdenhancement unit 742.

Meanwhile, each of the first resolution enhancement unit 735, the secondresolution enhancement unit 738, and the third resolution enhancementunit 742 may perform super resolution, peaking, LTI, anti-aliasingprocesses.

In this case, the first resolution enhancement unit 735, the secondresolution enhancement unit 738, and the third resolution enhancementunit 742 may perform resolution enhancement in a multi levelhierarchical structure or according to an image size. For example, thefirst resolution enhancement unit 735, the second resolution enhancementunit 738, and the third resolution enhancement unit 742 may performresolution enhancement with different filter sizes or differentfrequency bands.

Accordingly, it is possible to increase intensity or sharpness ofresolution enhancement without any side effect, and it is easy toperform tuning for each stage due to resolution enhancement processingin a multi level hierarchical structure.

FIG. 11 is a diagram referred to for describing multi-stage grayscaleenhancement.

Referring to the drawing, (a) of FIG. 11 represents an original image ofa received image signal 1150 a, (b) of FIG. 11 represents an image 1150b obtained as a result of multi-stage resolution enhancement, and (c) ofFIG. 11 represents an image 1150 c obtained as a result of single-stagegrayscale enhancement.

Referring to (b) of FIG. 11, unlike the received image signal 1150 a in(a) of FIG. 11 and the image 1150 c obtained as a result of single-stagegrayscale enhancement, an eye area 1110 is displayed more clearly and askin area 1115 around the eye has a delicate texture and appears clear.

Meanwhile, another characteristic of the signal processing device 170 ofthe present disclosure lies in process any image quality, includingquality of a High Frame Rate (HFR) image, through quality scalableprocessing.

To this end, the signal processing device 170 of the present disclosuremay apply a multi-stage image quality processing technique to an imagehaving a first vertical synchronization frequency (e.g., 60 Hz) or less,as described above, and may apply a single-stage image qualityprocessing technique, not the multi-stage image quality processingtechnique, to an image having a vertical synchronization frequencygreater than the first vertical synchronization frequency (e.g., 60 Hz).

To this end, it is possible to freely connect an input and an output ofeach core, remap an input/output of each unit of the image qualityprocessor, and perform splitting and merging to distribute inputs tomulti cores. In this case, a splitting method may be classified into aspatial splitting method and a temporal splitting method. It will bedescribed in more detail with reference to FIG. 12.

FIG. 12 is a block diagram of a signal processing apparatus 170 baccording to another embodiment of the present disclosure.

Referring to the drawing, the signal processing device 170 b, especiallyan image quality processor 635, according to another embodiment of thepresent disclosure may reconfigure the structure of a first reductionunit 710 and a second enhancement unit 750 in a scalable manneraccording to a vertical synchronization frequency of a received imagesignal.

That is, the image quality processor 635 may include a first noisereduction unit 715 a for performing first-stage noise reduction based ona received image signal when a vertical synchronization frequency of thereceived image signal is a first vertical synchronization frequency(e.g., 60 Hz), and a second noise reduction unit 720 for performingsecond-stage noise reduction based on an image received from the firstnoise reduction unit 715 a .

Meanwhile, when a vertical synchronization frequency of a received imagesignal is a second vertical synchronization frequency (e.g., 120 Hz)higher than the first vertical synchronization frequency (e.g., 60 Hz),the image quality processor 635 may configure the first noise reductionunit 715 a and the second noise reduction unit 720 in parallel so as toperform single-stage noise reduction.

For example, when the vertical synchronization frequency of the receivedimage signal is the first vertical synchronization frequency (e.g., 60Hz), the image quality processor 635 may, similarly as shown in FIG. 7,configure a first reduction unit 710 for multi-stage noise reduction andan enhancement unit 750 for multi-stage resolution enhancement.

The first reduction unit 710 may include a plurality of noise reductionunits 715 a and 720 for processing temporal noise and spatial noise, andthe enhancement unit 750 may include a plurality of resolutionenhancement units 735, 738, and 742 a for multi-stage resolutionenhancement, and a frame rate converter (FRC) 739.

When a vertical synchronization frequency of a received image signal isa second vertical synchronization frequency higher than a first verticalsynchronization frequency, an image splitter 798 of the signalprocessing device 170 b may split the received image signal by a spatialsplitting method or a temporal splitting method.

Split images may be respectively input to the noise reduction units 715a and 720, and each of the noise reduction units 715 a and 720 mayperform noise reduction.

Unlike the first vertical synchronization frequency, the split imagesmay go through single-noise reduction (including temporal noisereduction and spatial noise reduction), not multi-stage noise reduction.

In addition, data output from each of the noise reduction units 715 aand 720 may be merged by an image merger 799. In addition, resolutionenhancement may be performed by the third resolution enhancement unit742 b.

As such, multi-stage noise reduction and multi-stage resolutionenhancement may be performed on a received image signal of the firstvertical synchronization frequency, and single-stage noise reduction andsingle-stage resolution enhancement may be performed on a received imagesignal of the second vertical synchronization frequency.

It is because the received image signal of the second verticalsynchronization frequency has a better quality and thus noise reductionand resolution enhancement is possible in a single stage rather than inmultiple stages.

As such, by changing a noise reduction method and a resolutionenhancement method according to a vertical synchronization frequency ofa received image signal, it is possible to perform quality scalableprocessing and thus process any image quality, including quality of aHFR image.

Meanwhile, another characteristic of the signal processing device 170 ofthe present disclosure lies in analyzing an image to discover an objectand enhance a stereoscopic effect of the object.

To this end, the object stereoscopic effect enhancement unit 745 mayextract an object area and a background area from a received imagesignal, perform contrast enhancement in the object area, and reduceluminance of the background area.

That is, the object stereoscopic effect enhancement unit 745 may processan object and a background differently, and extract a degree of theobject relative to the background without given information about theobject. In addition, a sense of inconsistency between the processedobject and background may be minimized, preventing side effects.

The object stereoscopic effect enhancement unit 740 may output a secondimage signal with a background area of luminance which is lower thanluminance of a background area of a first input image signal input tothe image analyzer 610. Accordingly, a stereoscopic effect of an objectmay be enhanced.

Meanwhile, the object stereoscopic enhancement unit 740 may output asecond image signal which is contrast-processed, by performing contrastenhancement based on an object area in the first input image signalinput to the image analyzer 610. In this case, it is desirable thatcontrast of the object area of the first image signal is higher thancontrast of an object area of the second image signal. Accordingly, astereoscopic effect of the object may be enhanced.

Meanwhile, the image analyzer 610 may calculate a probability for theobject area of the first image signal and a probability for thebackground area of the first image signal. Such information may be inputto the object stereoscopic effect enhancement unit 740.

The object stereoscopic effect enhancement unit 740 may perform signalprocessing such that the luminance of the background area of the secondimage signal decreases in disproportion to the probability for thebackground area. Accordingly, a stereoscopic effect of the object may beenhanced further.

Meanwhile, the object stereoscopic effect enhancement unit 740 mayperform signal processing such that the contrast of the object area ofthe second image signal increases in proportion to the probability forthe object area. Accordingly, a stereoscopic effect of the object may beenhanced further.

Meanwhile, the image analyzer 610 may receive a first image signalcorresponding to displaying at least an object and a background,identify information of the object from the first image signal, andidentify information of the background from the first image signal.

Meanwhile, the object stereoscopic effect enhancement unit 745 maydetermine a sharpness of the object using the identified information ofthe object, increase contrast of the object to enhance the first imagesignal using the identified information of the object based on thedetermined sharpness, decrease luminance of the background in theenhanced first image signal using the identified information of thebackground based on the determined sharpness, and output the enhancedfirst image signal.

Meanwhile, when the sharpness of the object is a first sharpness level,the contrast of the object may be changed by a first contrast amount.

Meanwhile, when the sharpness of the object is a second sharpness levelhigher than the first sharpness level, the contrast of the object may bechanged by a second contrast amount greater than the first contrastamount.

Meanwhile, as the sharpness of the object increases, the objectstereoscopic effect enhancement unit 745 may increase the contrast ofthe object by a greater amount.

Meanwhile, when the sharpness of the object is the first sharpness, theluminance of the background may be changed by the first luminance level.

Meanwhile, when the sharpness of the object is a second sharpness levelhigher than the first sharpness level, the luminance of the backgroundmay be changed by a second luminance amount greater than the firstluminance amount.

Meanwhile, as the sharpness of the object increases, the objectstereoscopic effect enhancement unit 745 may decrease the luminance ofthe background by a greater amount.

Meanwhile, the signal processing device 170 is associated with a displaypanel for displaying the first image signal and a peak luminance ofdisplay panel is increased in response to the decreased luminance of thebackground.

Meanwhile, the image analyzer 610 may determine a ratio of a size of theobject to the background in the first image signal, and the amount ofdecrease of the luminance of the background is based on the determinedratio.

Meanwhile, when the determined ratio is a first ratio, the amount ofdecrease of the luminance of the background is a first luminance amount,and when the determined ratio is a second ratio smaller than the firstratio, the amount of decrease of the luminance of the background is asecond luminance amount smaller than the first luminance amount.

Meanwhile, as the determined ratio increases, the object stereoscopiceffect enhancement unit 745 may decrease the luminance of the backgroundby a greater amount.

Meanwhile, the image analyzer 610 may determine a ratio of a size of theobject to the background in the first image signal, and the amount ofincrease of the contrast of the object is based on the determined ratio.

Meanwhile, when the determined ratio is a first ratio, the amount ofincrease of the contrast of the object is a first contrast amount, andwhen the determined ratio is a second ratio smaller than the firstratio, the amount of increase of the contrast of the object is a secondcontrast amount smaller than the first contrast amount.

Meanwhile, as the determined ratio increases, the object stereoscopiceffect enhancement unit 745 may increase the contrast of the object by agreater amount.

The object stereoscopic effect enhancement unit 740 will be described inmore detail with reference to FIGS. 13A to 16B.

FIG. 13A is an inner block diagram of the object stereoscopic effectenhancement unit shown in FIG. 7.

Referring to the drawing, the object stereoscopic effect enhancementunit 745 may include a foreground/background candidate acquisition unit1310 for acquiring a foreground/background area candidate, aforeground/background probability model establisher 1320 forestablishing a foreground/background probability model, an objectinformation acquisition unit 1330 for acquiring object information, andan object/background-based image quality processor 1340 for processingimage quality based on an object/background.

FIG. 13B is an example of an inner block of the foreground/backgroundarea acquisition unit 1310 shown in FIG. 13A.

Referring to the drawing, the foreground/background area candidateacquisition unit 1310 may include a feature extractor 1350, a histogramaccumulator 1360, a histogram analyzer 1370, and a foreground areacandidate setting unit 1380.

The feature extractor 1350 may extract a feature from each pixel of animage. For example, the feature extractor 1350 may extract edgeinformation, skin color, and the like as features.

The histogram accumulator 1360 may accumulate each extracted feature ina histogram in horizontal and vertical directions and analyze thehistogram.

The histogram analyzer 1370 may estimate a position of a foreground frominformation on the analyzed histogram.

The foreground area candidate setting unit 1380 may set a quadrangularforeground area candidate in an image and acquire coordinates of thequadrangular foreground area candidate.

FIG. 14A is a flowchart referred to for describing operation of theforeground/background probability model establishing unit 1320 shown inFIG. 13A.

Referring to the drawing, the foreground/background probability modelestablishing unit 1320 may determine whether a pixel of a received imagesignal belongs to a foreground area (S1405).

In addition, when a pixel of the received image signal belongs to theforeground area, the foreground/background probability modelestablishing unit 1320 may accumulate a foreground histogram (S1410) andcalculate a foreground probability (S1413).

Meanwhile, when a pixel of a received image signal does not belong tothe foreground area, the foreground/background probability modelestablishing unit 1320 may determine that the corresponding pixelbelongs to a background area, accumulate a background histogram (S1420),and calculate a background probability (S1423).

Accordingly, using a histogram for each area in a received image signal,it is possible to estimate a probability for a pixel to belong to acorresponding area.

FIG. 14B is a block diagram of the object information acquisition unit1330 shown in FIG. 7.

Referring to the drawing, the object information acquisition unit 1330may include a background/foreground differential generator 1452 forgenerating a background/foreground differential, an elliptic gaingenerator 1454 for generating an elliptic gain, a multiplier 1455, aspatial filter 1457, and a temporal filter 1459.

The elliptic gain generator 1454 may minimize a sense of inconsistencybetween an object and a background, by performing coarse modeling on anobject outline.

The object information acquisition unit 1330 may calculate a degree of abasic object by multiplying a differential between a foregroundprobability and a background probability, which is obtained by thebackground/foreground differential generator 1452, by an elliptic gain,which is obtained by the elliptic gain generator 1454 based on aforeground area candidate.

Meanwhile, in order to reduce noise and achieve stability, the objectinformation acquisition unit 1330 may obtain a degree of a final objectby performing spatial and temporal filtering by the spatial filter 1457and the temporal filter 1459.

Meanwhile, another characteristic of the signal processing apparatus 170of the present disclosure lies in analyzing an image to discover anobject and enhance a stereoscopic effect of the object. It will bedescribed in more detail with reference to FIG. 15.

FIG. 15 is a block diagram of the object/background-based image qualityprocessor 1340 shown in FIG. 7.

Referring to the drawing, the object/background-based image qualityprocessor 1340 may perform image-quality processing based on a receivedimage signal and final object degree information acquired by the objectinformation acquisition unit 1330.

To this end, the object/background-based image quality processor 1340may include an object image quality processor 1510 for objectimage-quality processing based on a received image signal and finalobject degree information, a background image quality processor 1520 forbackground image quality processing based on the received image signaland the final object degree information, and an image merger 1530.

The image merger 1530 may merge an output from the object image qualityprocessor 1510 and the background image quality processor 1520 andoutput a merge result.

In particular, the image merger 1530 may output a final image by mergingthe output from the object image quality processor 1510 and the outputfrom the background image quality processor 1520 according to intensityor sharpness of a final object.

For example, the image merger 1530 may change contrast of an object orluminance of a background area and a foreground area according tointensity or sharpness of a final object.

Specifically, the image merger 1530 may change contrast or luminancesuch that contrast of the object increases and the lower luminance ofthe background area decreases disproportionally to intensity orsharpness of the final object. Accordingly, a stereoscopic effect of theobject may be enhanced.

Meanwhile, the object/background-based image quality processor 1340 mayenhance an image stereoscopic effect by performing a processingoperation based on an object map.

Meanwhile, the object/background-based image quality processor 1340 mayadd a stereoscopic effect by enhancing contrast in an object area.

Meanwhile, the object/background-based image quality processor 1340 mayincrease peak luminance of the organic light emitting panel 210 byreducing brightness in a background area.

FIGS. 16A and 16B are diagrams referred to for describing an objectprocessing effect.

FIG. 16A illustrates an image 1605 a which is output when an objectprocessing operation is not performed, and FIG. 16B illustrates an image1605 b which is output when an object processing operation is performed.

As the object processing operation is performed, a stereoscopic effectof an object area 1610 in the image 1605 b may improve and peakluminance thereof may increase.

Meanwhile, another characteristic of the signal processing device 170 ofthe present disclosure lies in operating in a hierarchical AI structurein which lower-level AI is used to make a determination regarding eachIP unit and upper-level AI is used to make a determination regarding thewhole. It will be described in more detail with reference to FIG. 17.

FIG. 17 is a block diagram of a signal processing device according toanother embodiment o the present disclosure.

Referring to the drawing, a signal processing device 170C according toanother embodiment of the present disclosure may include an imageanalyzer 610 for perform AI analysis on an entire image, and an imagequality processor 635 c.

The image quality processor 635 c may include first to sixth AI imageanalyzer 1700 a to 1700 f, a noise reduction unit 1710, an IPC unit1720, a grayscale extension unit 1730, a resolution enhancement unit1740, an object stereoscopic effect enhancement unit 1750, and a colorcontrast enhancement unit 1760 for enhancing color or contrast.

The noise reduction unit 1710 and the resolution enhancement unit 1740may operate in multiple stages, as described above.

Meanwhile, for the sake of the noise reduction unit 1710, the IPC unit1720, the grayscale extension unit 1730, the resolution enhancement unit1740, the object stereoscopic effect enhancement unit 1750, and thecolor contrast enhancement unit 1760, the first to sixth AI imageanalyzer 1700 a to 1700 f may analyze an image for each core.

In addition, the image analyzer 610 may analyze an additional entireimage using core-unit information collected by the first to sixth AIimage analyzers 1700 a to 1700 f, and provide corresponding setting.

That is, the signal processing device 170C according to anotherembodiment of the present disclosure is characterized by having ahierarchical structure when it comes to artificial intelligenceprocessing.

Meanwhile, for the noise reduction unit 1710, the first image analyzer1700 a may measure noise and compute image motion. For the IPC unit1720, the second image analyzer 1700 b may determine a cadence andcompute subtitle motion and an image break level. For the grayscaleextension unit 1730, the third image analyzer 1700 c may compute adegree of compression of an original image, brightness, and resolution.For the resolution enhancement unit 1740, the fourth image analyzer 1700d may compute a frequency, a total edge quantity, and a total texturequantity. For the object stereoscopic effect enhancement unit 1750, thefifth image analyzer 1700 e may compute image distribution, the numberof objects, presence of a human, and a foreground-background ratio. Forthe contrast enhancement unit 1760, the sixth image analyzer 1700 f mayanalyze a histogram, and determine a pattern and continuity ofgrayscale.

In particular, the fifth image analyzer 1700 e may receive a first imagesignal and separate an object area and a background area of the firstimage signal.

In addition, the fifth image analyzer 1700 e may compute a probabilityfor the object area of the first image signal and a probability for thebackground area of the first image signal, and transmit information onthe computed probabilities to the object stereoscopic effect enhancementunit 1750.

That is, the fifth image analyzer 1700 e in FIG. 17 corresponds tooperation of the image analyzer 610, and the object stereoscopic effectenhancement unit 1750 in FIG. 17 may correspond to operation of theobject stereoscopic effect enhancement unit 740.

In conclusion, according to an embodiment of the present disclosure, itis possible to effectively enhance image quality by performingmulti-stage image quality processing.

In particular, in multi-stage noise production, double noise reductionis employed, and thus, the effect of the noise reduction may improve andeven noise occurring due to an algorithm such as an IPC algorithm may bereduced.

Meanwhile, three-stage grayscale reproduction is employed, and thus, alost grayscale bit of a received image signal may be reproduced, therebyproviding a smoother picture.

Meanwhile, four-stage grayscale restoration and extension is employed,and thus, a loss of grayscale accompanying with an enhancement processmay be restored and a smoother and more dynamic output may be achievedwithout an aliasing error.

Meanwhile, multi-stage resolution enhancement makes it obtain a morenatural and strong resolution enhancement result.

Such a multi-stage image quality processing algorithm may be used toprocess a 120 Hz image and may be used to perform image quality engineprocessing based on an HFR image.

In addition, an artificial-intelligent (AI) image quality processingfeature such as detecting an object may be introduced and cores may beeffectively and organically connected with each other in a hierarchicalAI structure, so that an optimal image quality may be provided.

As is apparent from the above description, according to an embodiment ofthe present invention, there is provided a signal processing device andan image display apparatus including the same according to the presentinvention comprises: a first reduction unit to receive a image signaland reduce noise of the received image signal, and a second reductionunit to perform grayscale amplification based on the image signal fromthe first reduction unit, wherein the second reduction unit isconfigured to perform the grayscale amplification so that upper-limitlevel of grayscale of the image signal from the first reduction unit isgreater than upper-limit level of grayscale of an OSD signal.Accordingly, an OSD area may be expressed uniformly, regardless ofambient luminance.

In particular, the second reduction unit may not perform grayscaleextension on the OSD signal so that the OSD area may be expresseduniformly, regardless of ambient luminance.

The OSD signal may be input to the second reduction unit, and the secondreduction unit may perform grayscale extension on an area other than theOSD area corresponding to the OSD signal based on coordinate informationof the OSD signal. Accordingly, the OSD area may be expressed uniformly,regardless of ambient luminance.

A High Dynamic Range (HDR) processor according to an embodiment of thepresent disclosure may receive an image signal and perform grayscaleconversion on the received image signal, the first reduction unitperform noise reduction based on a grayscale-converted image signalreceived from the HDR processor, and the second reduction unit mayperform grayscale extension based on a noise-reduced image signalreceived from the first reduction unit, so that an upper-limit level ofgrayscale extended by the second reduction unit is changed according toa grayscale conversion mode implemented in the HDR processor.Accordingly, expression of high grayscale may improve.

In particular, an upper-limit level of maximum grayscale may be changedand thus expression of high grayscale of a received image may improve.

When a second grayscale conversion mode in which low grayscale is lesshighlighted is selected from a first grayscale conversion mode and thesecond grayscale mode and implemented in the HDR processor, the secondreduction unit may perform a fourth grayscale conversion mode in whichan upper-limit level of grayscale is higher than an upper-limit level ofgrayscale level of a third grayscale conversion mode. Accordingly,expression of high grayscale may improve.

The HDR processor may implement the first grayscale conversion mode, inwhich low grayscale is highlighted compared to high grayscale and thehigh grayscale is saturated, or the second grayscale conversion mode inwhich the low grayscale and the high grayscale are uniformly converted.When the HDR processor implements the second grayscale conversion mode,the second reduction unit may implement the fourth grayscale conversionmode in which the upper-limit level of grayscale is higher than theupper-limit level of grayscale level of the third grayscale conversionmode. Accordingly, expression of high grayscale may improve.

The second reduction unit may perform grayscale extension on an areawith first luminance or higher in a received image signal. Accordingly,expression of high grayscale may improve.

Meanwhile, the first reduction unit may perform multi-stage noisereduction based on a grayscale-converted image signal received from theHDR processor. Accordingly, image quality may be enhanced gradually.

Meanwhile, as multi-stage noise reduction is performed, dual noisereduction is employed to efficiently reduce noise of an original signaland reduce even noise occurring due to an algorithm such as anInterlaced Progressive Conversion (IPC) algorithm.

Meanwhile, due to three-stage grayscale reproduction, a lost grayscalebit of a received image signal is reproduced, thereby providing asmoother picture.

In addition, multi-stage grayscale extension may be performed using thefirst reduction unit and the second reduction unit, and accordingly,image quality may improve.

Meanwhile, the enhancement unit positioned between the first reductionunit and the second reduction unit performs multi-stage resolutionprocessing based on a noise-reduced image signal received from the firstreduction unit, thereby obtaining a more natural and strong resolutionenhancement result.

Meanwhile, using a four-stage grayscale restoring process, a loss ofgrayscale accompanying with an internal enhancement process, therebyobtaining a smoother and more dynamic output without an aliasing error.

In addition, an artificial-intelligent (AI) image quality processingfeature such as detecting an object may be introduced and cores may beefficiently and organically connected with each other in a hierarchicalAI structure, thereby providing an optimal image quality.

Meanwhile, when a vertical synchronization frequency of a received imagesignal is a first vertical synchronization frequency, multi-stage noisereduction is performed. When a vertical synchronization frequency of areceived image signal is a second vertical synchronization frequencyhigher than the first vertical synchronization frequency, single-stagenoise reduction is performed. Thus, it is possible to process any imagequality, including quality of a High Frame Rate (HFR) image, throughquality scalable processing. In particular, it is possible to processany image quality without additional costs.

Although the exemplary embodiments have been illustrated and described,embodiments are not limited to the above-described particularembodiments, various modifications are possible by those skilled in theart without departing from the scope and spirit as disclosed in theaccompanying claims and these modifications should not be understoodseparately from the scope and spirit.

What is claimed is:
 1. A signal processing device of an image displayapparatus, the signal processing device comprising: a grayscale extenderconfigured to: receive an image signal and an on screen display (OSD)signal; amplify an upper-limit level of a grayscale of the image signalfrom a first level to a second level greater than the first level;change luminance interval of the amplified grayscale of the image signalfrom a first luminance interval to a second luminance interval moredetailed than the first luminance interval, wherein the grayscaleextender does not amplify an upper-limit level of a maximum grayscale ofthe OSD signal, wherein the second level of the grayscale of the imagesignal is greater than then upper-limit level of a grayscale of the OSDsignal.
 2. The signal processing device of claim 1, wherein the numberof displayable luminance in case of the first luminance interval isgreater than the number of displayable luminance in case of the secondluminance interval.
 3. The signal processing device of claim 1, whereinthe OSD signal is input to the grayscale extender, and wherein thegrayscale extender is further configured to perform grayscaleamplification on an area except for an OSD area corresponding to the OSDsignal.
 4. The signal processing device of claim 1, further comprising:a high definition resolution (HDR) processor configured to receive theimage signal and perform grayscale conversion on the image signalreceived by the HDR processor; and a reducer configured to reduce noiseof grayscale-converted image signal received from the HDR processor, andwherein the upper-limit level of the grayscale amplified by thegrayscale extender is varied according to a mode of the grayscaleconversion, a first grayscale conversion mode, performed by the HDRprocessor.
 5. The signal processing device of claim 4, wherein when asecond grayscale conversion mode, in which a low grayscale is notemphasized compared to the first gradation mode, is performed by the HDRprocessor, the grayscale extender is further configured to perform afourth grayscale conversion mode corresponding to the second grayscaleconversion mode between a third grayscale conversion mode correspondingto the first grayscale conversion mode and the fourth grayscaleconversion mode, and wherein an upper-limit level of a grayscale of thefourth grayscale conversion mode is greater than an upper-limit level ofa grayscale of the third grayscale conversion mode.
 6. The signalprocessing device of claim 4, wherein the HDR processor is furtherconfigured to perform grayscale conversion based on the first grayscaleconversion mode in which a low grayscale is highlighted compared to ahigh grayscale and the high grayscale is saturated, or based on a secondgrayscale conversion mode in which a low grayscale and a high grayscaleare converted uniformly, wherein when the second grayscale conversionmode is performed by the HDR processor, the grayscale extender isfurther configured to perform a fourth grayscale conversion modecorresponding to the second grayscale conversion mode between a thirdgrayscale conversion mode corresponding to the first grayscaleconversion mode and the fourth grayscale conversion mode, and wherein anupper-limit level of a grayscale of the fourth grayscale conversion modeis greater than an upper-limit level of a grayscale of the thirdgrayscale conversion mode.
 7. The signal processing device of claim 6,wherein an output value of the low grayscale in the second grayscaleconversion mode is smaller than an output value of the low grayscale inthe first grayscale conversion mode.
 8. The signal processing device ofclaim 4, wherein the reducer is further configured to performmulti-stage noise reduction based on the grayscale-converted imagesignal received from the HDR processor.
 9. The signal processing deviceof claim 4, wherein the reducer is further configured to increase agrayscale resolution in a first-stage, and wherein the grayscaleextender is further configured to increase a grayscale resolution in asecond-stage.
 10. The signal processing device of claim 4, furthercomprising an enhancement processor positioned between the reducer andthe grayscale extender and configured to perform multi-stage resolutionenhancement based on a noise-reduced image signal received from thereducer.
 11. The signal processing device of claim 4, wherein thereducer comprises a plurality of noise reducers configured to reducenoise of the received image signal in multiple stages, and wherein eachof the plurality of noise reducers comprises: a temporal noise reducerconfigured to perform temporal noise reduction using previous framedata; and a spatial noise reducer configured to perform spatial noisereduction using data around current frame data.
 12. The signalprocessing device of claim 11, wherein when the received image signal isan interlaced video, a first noise reducer of the plurality of noisereducers is configured to perform interlaced progressive conversion. 13.The signal processing device of claim 1, wherein the grayscale extendercomprises: a first decontourer for performing first-stage decontouring;a second decontourer for performing second-stage decontouring; and aditherer for performing dithering.
 14. The signal processing device ofclaim 1, wherein the grayscale extender is further configured to performgrayscale extension on an area with a first luminance or a luminancehigher than the first luminance within the image signal.
 15. The signalprocessing device of claim 4, wherein the reducer comprises: a firstnoise reducer for performing first-stage noise reduction based on thereceived image signal; a second noise reducer for performingsecond-stage noise reduction based on the image signal from the firstnoise reducer, wherein the grayscale extender is further configured toperform grayscale amplification based on the image signal from thesecond noise reducer, and wherein the grayscale extender is furtherconfigured to perform the grayscale amplification so that theupper-limit level of the grayscale of the image signal is greater thanthe upper-limit level of the grayscale of then OSD signal.
 16. Thesignal processing device of claim 15, wherein the OSD signal is input tothe grayscale extender, and wherein the grayscale extender is furtherconfigured to perform grayscale amplification on an area except for anOSD area corresponding to the OSD signal, based on coordinateinformation of the OSD signal.
 17. An image display apparatuscomprising: a display; and a signal processing device to output an imagesignal to the display, wherein the signal processing device comprises agrayscale extender configured to: receive an image signal and an onscreen display (OSD) signal; amplify an upper-limit level of a grayscaleof the image signal from a first level to a second level greater thanthe first level; change luminance interval of the amplified grayscale ofthe image signal from a first luminance interval to a second luminanceinterval more detailed than the first luminance interval, wherein thegrayscale extender does not amplify an upper-limit level of a maximumgrayscale of the OSD signal, wherein the second level of the grayscaleof the image signal is greater than then upper-limit level of agrayscale of the OSD signal.
 18. The image display apparatus of claim18, wherein the number of displayable luminance in case of the firstluminance interval is greater than the number of displayable luminancein case of the second luminance interval.
 19. The image displayapparatus of claim 18, wherein the OSD signal is input to the grayscaleextender, and wherein the grayscale extender is further configured toperform grayscale amplification on an area except for an OSD areacorresponding to the OSD signal.